import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;

/**
 * @author Sebastian
 * @version 2.0
 * @date 2024/8/12 10:30
 */
// 三数之和
    // https://leetcode.cn/problems/3sum/description/
public class Solution15 {
    public List<List<Integer>> threeSum(int[] nums) {
        List<List<Integer>> res = new LinkedList<>();
        Arrays.sort(nums);
        for (int i = 0; i < nums.length; i++) {
            if (nums[i] > 0) {
                return res;
            }
            if (i > 0 && nums[i] == nums[i - 1]) {
                continue;
            }
            int left = i + 1;
            int right = nums.length - 1;
            while (left < right) {
                int sum = nums[i] + nums[left] + nums[right];
                if (sum < 0) left++;
                if (sum > 0) right--;
                if (sum == 0) {
                    res.add(Arrays.asList(nums[i], nums[left],nums[right]));
                    while (left < right && nums[left] == nums[left + 1]) left++;
                    while (left < right && nums[right] == nums[right - 1]) right--;
                }
                left++;
                right--;
            }
        }
        return res;
    }
}
